Thai policemen rehearse anti-riot manoeuvres at Government House in Bangkok on September 19, 2009 in preparation for a rally to mark the third anniversary of a military coup against former prime minister Thaksin Shinawatra. Thousands of red-shirted protesters rallied in Bangkok amid tight security after the government imposed a Draconian internal security law in the centre of the capital for the latest demonstrations and deployed more than 9,000 soliders and police to guard key locations.